/**
  ******************************************************************************
  * @file    PWR/PWR_STANDBY_RTC/Src/main.c
  * @author  MCD Application Team
  * @brief   This sample code shows how to use STM32L1xx PWR HAL API to enter
  *          and exit the Standby mode using RTC.
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; Copyright (c) 2017 STMicroelectronics.
  * All rights reserved.</center></h2>
  *
  * This software component is licensed by ST under BSD 3-Clause license,
  * the "License"; You may not use this file except in compliance with the
  * License. You may obtain a copy of the License at:
  *                        opensource.org/licenses/BSD-3-Clause
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "main.h"

/** @addtogroup STM32L1xx_HAL_Examples
  * @{
  */

/** @addtogroup PWR_STANDBY_RTC
  * @{
  */

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* RTC handler declaration */
RTC_HandleTypeDef RTCHandle;
static __IO uint32_t TimingDelay;

/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
static void SystemPower_Config(void);
static void Error_Handler(void);

/* Private functions ---------------------------------------------------------*/

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{
  /* STM32L1xx HAL library initialization:
       - Configure the Flash prefetch
       - Systick timer is configured by default as source of time base, but user 
         can eventually implement his proper time base source (a general purpose 
         timer for example or other time source), keeping in mind that Time base 
         duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and 
         handled in milliseconds basis.
       - Set NVIC Group Priority to 4
       - Low Level Initialization
     */
  HAL_Init();

  /* Configure LED2 */
  BSP_LED_Init(LED2);

  /* Configure the system clock to 32 MHz */
  SystemClock_Config();

  /* Configure the system Power */
  SystemPower_Config();

  /* Check and handle if the system was resumed from StandBy mode */ 
  if(__HAL_PWR_GET_FLAG(PWR_FLAG_SB) != RESET)
  {
    /* Clear Standby flag */
    __HAL_PWR_CLEAR_FLAG(PWR_FLAG_SB); 
  }
  
  /* Insert 5 seconds delay */
  HAL_Delay(5000);
  
  /* The Following Wakeup sequence is highly recommended prior to each Standby mode entry
    mainly  when using more than one wakeup source this is to not miss any wakeup event.
    - Disable all used wakeup sources,
    - Clear all related wakeup flags, 
    - Re-enable all used wakeup sources,
    - Enter the Standby mode.
  */
  /* Disable all used wakeup sources*/
  HAL_RTCEx_DeactivateWakeUpTimer(&RTCHandle);
  
  /* Re-enable all used wakeup sources*/
  /* ## Setting the Wake up time ############################################*/
  /*  RTC Wakeup Interrupt Generation:
    Wakeup Time Base = (RTC_WAKEUPCLOCK_RTCCLK_DIV /(LSI))
    Wakeup Time = Wakeup Time Base * WakeUpCounter 
      = (RTC_WAKEUPCLOCK_RTCCLK_DIV /(LSI)) * WakeUpCounter
      ==> WakeUpCounter = Wakeup Time / Wakeup Time Base
  
    To configure the wake up timer to 4s the WakeUpCounter is set to 0x1FFF:
    RTC_WAKEUPCLOCK_RTCCLK_DIV = RTCCLK_Div16 = 16 
    Wakeup Time Base = 16 /(~39.000KHz) = ~0,410 ms
    Wakeup Time = ~4s = 0,410ms  * WakeUpCounter
      ==> WakeUpCounter = ~4s/0,410ms = 9750 = 0x2616 */
  HAL_RTCEx_SetWakeUpTimer_IT(&RTCHandle, 0x2616, RTC_WAKEUPCLOCK_RTCCLK_DIV16);
  
  /* Clear all related wakeup flags */
  __HAL_PWR_CLEAR_FLAG(PWR_FLAG_WU);
  
  /* Enter the Standby mode */
  HAL_PWR_EnterSTANDBYMode();
  
  while (1)
  {
  }
}

/**
  * @brief  System Clock Configuration
  *         The system Clock is configured as follow :
  *            System Clock source            = PLL (HSI)
  *            SYSCLK(Hz)                     = 32000000
  *            HCLK(Hz)                       = 32000000
  *            AHB Prescaler                  = 1
  *            APB1 Prescaler                 = 1
  *            APB2 Prescaler                 = 1
  *            HSI Frequency(Hz)              = 16000000
  *            PLLMUL                         = 6
  *            PLLDIV                         = 3
  *            Flash Latency(WS)              = 1
  * @retval None
  */
void SystemClock_Config(void)
{
  RCC_ClkInitTypeDef RCC_ClkInitStruct = {0};
  RCC_OscInitTypeDef RCC_OscInitStruct = {0};

  /* Enable HSE Oscillator and Activate PLL with HSE as source */
  RCC_OscInitStruct.OscillatorType      = RCC_OSCILLATORTYPE_HSI;
  RCC_OscInitStruct.HSIState            = RCC_HSI_ON;
  RCC_OscInitStruct.HSICalibrationValue = RCC_HSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.PLL.PLLState        = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource       = RCC_PLLSOURCE_HSI;
  RCC_OscInitStruct.PLL.PLLMUL          = RCC_PLL_MUL6;
  RCC_OscInitStruct.PLL.PLLDIV          = RCC_PLL_DIV3;
  if (HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    Error_Handler();
  }

  /* Set Voltage scale1 as MCU will run at 32MHz */
  __HAL_RCC_PWR_CLK_ENABLE();
  __HAL_PWR_VOLTAGESCALING_CONFIG(PWR_REGULATOR_VOLTAGE_SCALE1);
  
  /* Poll VOSF bit of in PWR_CSR. Wait until it is reset to 0 */
  while (__HAL_PWR_GET_FLAG(PWR_FLAG_VOS) != RESET) {};

  /* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2
  clocks dividers */
  RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;
  if (HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_1) != HAL_OK)
  {
    Error_Handler();
  }
}
/**
  * @brief  System Power Configuration
  *         The system Power is configured as follow :
  *            + RTC Clocked by LSI
  *            + VREFINT OFF, with fast wakeup enabled
  *            + No IWDG
  *            + Automatic Wakeup using RTC clocked by LSI (after ~4s)
  * @param  None
  * @retval None
  */
static void SystemPower_Config(void)
{
  /* Enable Ultra low power mode */
  HAL_PWREx_EnableUltraLowPower();

  /* Enable the fast wake up from Ultra low power mode */
  HAL_PWREx_EnableFastWakeUp();

  /* Configure RTC */
  RTCHandle.Instance = RTC;
  /* Set the RTC time base to 1s */
  /* Configure RTC prescaler and RTC data registers as follow:
    - Hour Format = Format 24
    - Asynch Prediv = Value according to source clock
    - Synch Prediv = Value according to source clock
    - OutPut = Output Disable
    - OutPutPolarity = High Polarity
    - OutPutType = Open Drain */
  RTCHandle.Init.HourFormat = RTC_HOURFORMAT_24;
  RTCHandle.Init.AsynchPrediv = RTC_ASYNCH_PREDIV;
  RTCHandle.Init.SynchPrediv = RTC_SYNCH_PREDIV;
  RTCHandle.Init.OutPut = RTC_OUTPUT_DISABLE;
  RTCHandle.Init.OutPutPolarity = RTC_OUTPUT_POLARITY_HIGH;
  RTCHandle.Init.OutPutType = RTC_OUTPUT_TYPE_OPENDRAIN;
  if(HAL_RTC_Init(&RTCHandle) != HAL_OK)
  {
    /* Initialization Error */
    Error_Handler(); 
  }
}


/**
  * @brief  This function is executed in case of error occurrence.
  * @param  None
  * @retval None
  */
static void Error_Handler(void)
{
  /* Turn on the LED2 */
  BSP_LED_On(LED2);
  while(1)
  {
  }
}

#ifdef  USE_FULL_ASSERT

/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */

  /* Infinite loop */
  while (1)
  {
  }
}
#endif

/**
  * @}
  */

/**
  * @}
  */

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
